Oregon Invasive Weed Awareness Week focuses on water, May 18

Governor Brown has proclaimed May 17-23 as Oregon Invasive Weed Awareness Week, signifying the importance of the state’s long battle with noxious weeds. The week provides another opportunity to educate Oregonians about the value of invasive weed detection and control efforts in protecting natural resources and agricultural production. This year’s theme is WATER– Weeds Attack Threatened Environmental Resources. The acronym flows perfectly with the state’s desire to protect water quality and water quantity. “Most of the 128 state listed noxious weeds have some impact on watershed health as a whole,” says Tim Butler, manager of the Oregon Department of Agriculture’s Noxious Weed Control Program. “A lot of the aquatic weed species directly impact water systems. But even terrestrial weeds impact the upper reaches of watersheds that filter into our streams, rivers, and other water bodies. With many of these species, if we can get to them early and prevent them from getting established before they become significant, we can help restore watershed health in the state.” Early detection, rapid response. Those four words are at the core of ODA’s program to battle invasive weeds. The public plays a key role in helping fight back invading plants. “One of the first lines of defense in noxious weed management is to identify pathways and the manner in which these weeds get moved,” says Butler. “We really encourage people to look at what role they might be playing in the introduction or spread of invasive weeds.” That’s especially important in protecting watersheds. ODA is working on a new outreach campaign called “Play. Clean. Go.”, as a way to communicate to boaters and other recreationists to keep from spreading weeds from one water body to another. From cleaning boots to cleaning boats, Oregonians can be engaged by not adding to the problem. The new campaign will employ such tools as brochures, posters, and trail signs to get the word out. There are many success stories that give hope to future success in noxious weed management. One of ODA’s longest running battles with an undesirable plant has been waged against purple loosestrife, an invasive noxious weed that will outcompete native species and contribute to habitat degradation. Its sinister specialty is to infest wetlands and riparian zones. Ultimately, it can lead to impaired water quality. “Like so many other invasive species in Oregon, purple loosestrife is a bad actor and it doesn’t belong here,” says Butler. Oregon’s rivers, streams, ponds, marshes, and wetlands are vulnerable. Quite simply, an increase in purple loosestrife means a decrease in native plants, which leads to fewer native insects that are important components in the food chain for young salmon and other aquatic species. When the leaves of purple loosestrife break down, they release relatively high levels of nitrogen in the water that could lead to algae blooms and poor water quality. ODA has more than a decade of good results from using biocontrol, or beneficial insects and other organisms, on purple loosestrife. The leaf-eating beetle Gallerucella has had the greatest success. Most of the Baskett Slough National Wildlife Refuge west of Salem has been reclaimed from the showy noxious weed thanks to the beetle’s effectiveness. ODA modeling has shown that early intervention with biocontrol has kept loosestrife populations at less than one percent of what they could be in Oregon. In all regions of the state, officials are looking for ways to effectively fight emerging invasive weeds that specifically impact water. In Southeast Oregon, perennial pepperweed is aggressively invading wetlands in the Warner Basin of Lake County, impacting native plants and sensitive species. With no biocontrol agent available at this time, officials are currently implementing other integrated control methods on pepperweed. In Northeast Oregon, flowering rush was detected last year in surveys. Extremely invasive, this weed has been a major problem in Montana, Idaho, and Washington for years. With no silver bullet available, the best that can be done is to find the weed while it is still in small populations, and manually remove it. In Central Oregon, a recent culprit is yellow floating heart. This weed actually thrives in the water itself and has also been a problem in Western Oregon. The weed forms dense patches, excluding light for native species and creating stagnant areas with low oxygen. Thick mats of yellow floating heart limit fishing and access. ODA and other cooperators are working directly with landowners to treat infested sites. “This weed could have a dramatic impact on water resources, particularly in Central Oregon, as it can get into irrigation canals and ponds, and choke them off,” says Butler. “It’s a reminder that noxious weeds can impact water quantity as well as water quality.” In Southwest Oregon, the aquatic species Eurasian watermillfoil is impacting Howard Prairie Reservoir near Ashland. Heavily infested areas are clogging boat ramps and have choked off areas to the point that it is likely impacting the reservoir’s total water holding capacity. In Northwest Oregon, water primrose is one to keep an eye on. Among its impacts, infested waterways suffer drops in dissolved oxygen, which kills fish and invertebrates and reduces productivity. Waterfowl lose preferred food plants and feeding grounds. The Oregon State Weed Board recognized the threat of this invader and awarded grants to develop action management plans and implement control in Lane and Benton counties. All these challenges are being met with a firm resolve. The Oregon Department of Agriculture and a wide network of partners are on the battlefield daily, working to prevent, eradicate, or control invasive species. Success benefits agriculture and forestry, the state’s valuable natural habitats, and, ultimately, water quality. But despite the spotlight of Oregon Invasive Weed Awareness Week, the effort needs to be 52 weeks a year.